从Python中提取字符串。

I am new to Python and I have a String, I want to extract the numbers from the string. For example:

我是Python新手，我有一个字符串，我想从字符串中提取数字。例如:

str1 = "3158 reviews"print (re.findall('\d+', str1 ))

Output is ['4', '3']

输出是[' 4 ',' 3 ')

I want to get 3158 only, as an Integer preferably, not as List.

我只想得到3158，最好是整数，而不是列表。

6 个解决方案

#1

You can filter the string by digits using str.isdigit method,

可以使用string .isdigit方法对字符串进行筛选，

>>> int(filter(str.isdigit, str1))3158

#2

This code works fine. There is definitely some other problem:

这段代码工作正常。肯定还有其他问题:

>>> str1 = "3158 reviews">>> print (re.findall('\d+', str1 ))['3158']

#3

Your regex looks correct. Are you sure you haven't made a mistake with the variable names? In your code above you mixup total_hotel_reviews_string and str.

你的正则表达式是正确的。你确定变量名没有出错吗?在您上面的代码中，混合了total_hotel_reviews_string和str。

>>> import re>>> s = "3158 reviews">>> print re.findall("\d+", s)['3158']

#4

If the format is that simple (a space separates the number from the rest) then

如果格式很简单(空格将数字与其他数字分开)，那么

int(str1.split()[0])

would do it

会这么做

#5

My answer does not require any additional libraries, and it's easy to understand. But you have to notice that if there's more than one number inside a string, my code will concatenate them together.

我的答案不需要任何额外的库，而且很容易理解。但是你必须注意，如果一个字符串中有多个数字，我的代码将把它们连接在一起。

def Search_number_String(String):    index_list = []    del index_list[:]    for i, x in enumerate(String):        if x.isdigit() == True:            index_list.append(i)    start = index_list[0]    end = index_list[-1] + 1    number = String[start:end]    return number

#6

There may be a little problem with code from Vishnu's answer. If there is no digits in the string it will return ValueError. Here is my suggestion avoid this:

Vishnu的答案可能会有一点问题。如果字符串中没有数字，它将返回ValueError。我的建议是:

>>> digit = lambda x: int(filter(str.isdigit, x) or 0)>>> digit('3158 reviews')3158>>> digit('reviews')0

#1